Systems, devices, and methods for autonomous vehicle localization

ABSTRACT

Disclosed are systems, methods, and computer-readable storage media to control a vehicle. In one aspect, a method includes capturing point-cloud data representative of a surrounding of an autonomous vehicle with one or more LIDAR sensors, identifying a point in the point cloud data as a non-matching point in response to the point having no corresponding point in a map used to determine a position of the autonomous vehicle, determining whether the non-matching point is to be used in a determination of an overlap score based on one or more comparisons of the point cloud data and the map, determining the overlap score in response to the determining whether the non-matching point is to be used in the determination of the overlap score, determining a position of the autonomous vehicle based on the overlap score and the map, and controlling the autonomous vehicle based on the position.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.62/567,439, filed Oct. 3, 2017 and entitled “SYSTEMS, DEVICES, ANDMETHODS FOR IMPROVED AUTONOMOUS VEHICLE CONTROL.” The content of thisprior application is considered part of this application, and is herebyincorporated by reference in its entirety.

TECHNICAL FIELD

The present disclosure generally relates to the control of autonomousvehicles, and in particular to improving an ability to correlatelocation information in a map with location data obtained by a vehiclewhile in motion.

BACKGROUND

Control of autonomous vehicles may rely on comparisons between maps of alocal area and information acquired by on-board vehicle sensors. Thesesensors may rely, in various aspects, on one or more of optical, radio,and laser based technologies. The comparisons between the maps and thedata obtained by the vehicle sensors may enable to vehicle to identifyits position along a roadway, in real time, and make adjustments to itsposition and/or speed based on the identified position.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, which are not necessarily drawn to scale, like numeralsmay describe similar components in different views. Like numerals havingdifferent letter suffixes may represent different instances of similarcomponents. Some embodiments are illustrated by way of example, and notlimitation, in the figures of the accompanying drawings.

FIG. 1 is an overview diagram of an autonomous vehicle

FIG. 2 shows an example embodiment of a map data collection vehicle.

FIG. 3A is a block diagram of an example system to control thenavigation of a vehicle according to example embodiments of the presentdisclosure.

FIG. 3B is an example expanded view of an autonomous vehicle.

FIG. 4 is an expanded view of an example controller or vehicle computingsystem.

FIG. 5 shows example scenes captured by LIDAR sensor(s) of an autonomousvehicle and a map generating vehicle.

FIG. 6 is a visual representation of a best fit correspondence betweentwo sets of point cloud data representing two scenes respectively.

FIG. 7 shows the two sets of point cloud data.

FIG. 8 shows example two dimensional representations of point cloud dataused to determine an overlap score.

FIG. 9 illustrates tracing of a ray from a laser source to adestination.

FIG. 10 is an example of a comparison of point cloud data captured by anautonomous vehicle and data included in a map.

FIG. 11 is a flowchart of an example method of controlling an autonomousvehicle.

DETAILED DESCRIPTION

The description that follows includes systems, methods, techniques,instruction sequences, and computing machine program products thatembody illustrative embodiments of the disclosure. In the followingdescription, for the purposes of explanation, numerous specific detailsare set forth in order to provide an understanding of variousembodiments of the inventive subject matter. It will be evident,however, to those skilled in the art, that embodiments of the inventivesubject matter may be practiced without these specific details. Ingeneral, well-known instruction instances, protocols, structures, andtechniques are not necessarily shown in detail.

Maps of an autonomous system can be used to perceive the environment,detect objects, localize and control of autonomous vehicles. One type ofmap is a map that provides coordinates of certain map features, such asroads, addresses, points of interests, traffic information, and thelike. Such maps, sometimes referred to as coverage maps, can be used togenerate routing information from point A to point B. However, the mapsof an autonomous system for the function listed above may require higherfidelity representation of the world. For example, a map for autonomousvehicles (“AV Map”) may include a 3-D point cloud of the environment. Aswill be described below, such AV maps can be generated by driving amapping vehicle equipped with a sensor within an area being mapped. Themapping vehicle may drive a section of road a number of times togenerate a dense set of map data for the section of road. In this way,the map data represents the world from the perspective of the sensor onthe mapping vehicle. The map data can include geolocation metadata sothat the autonomous vehicle can determine the sensor data that isexpected at a given location.

Maps may be generated from data collected in a variety of environments.For example, some maps are generated based on data collected fromvehicles having roof mounted sensors, e.g., a LIDAR (Light Detection andRanging), RADAR (Radio Detection and Ranging), or Visual sensors (e.g.,a camera sensor). Other maps are generated from data collected byvehicles with sensors mounted on an extension platform. The extensionplatform may position the sensor substantially above the vehicle's roofline. Furthermore, while the data collected for maps may vary, vehiclesusing the maps for autonomous position determination may also havesensors that vary in their positions. For example, a small compact carmay have an LIDAR sensor located at a first distance from the groundwhile a large semi-tractor may have an LIDAR sensor positioned at alarger second distance. Thus, a sensor mounted to the top of a compactcar and to the top of a truck may generate different point cloudsbecause of the different perspectives.

Additionally, the angle of a sensor used to collect map data may alsovary from map to map. For example, some vehicles may be positioned in aslightly nose up attitude, resulting in the sensor being slightlyinclined with respect to the horizontal. Other map generating vehiclesmay have a nose down stance, resulting in the sensor line of sightfalling slightly below the horizontal.

The disclosed methods, devices, and systems provide for improvements inautonomous vehicles in a variety of environments, such as thosedescribed above. In some aspects disclosed, an autonomous vehiclegenerates an overlap score. The overlap score provides an indication ofhow well position information derived from three-dimensional LIDAR pointcloud captured by autonomous vehicle matches position information (e.g.point cloud data) included in a particular map at a particular locationand, in some embodiments, orientation. The autonomous vehicle generatesmultiple overlap scores from a single set of captured positioninformation by calculating the overlap score at different candidatepositions within the particular map. Each overlap score provides anindication of how likely the corresponding candidate positioncorresponds to the vehicle's true position within the map data. Acandidate location corresponding to map data having the best overlapscore may be considered the best approximation of the vehicle's positionin some aspects.

As discussed above, in some embodiments, an autonomous vehicle's sensorthat is collecting the position information is configured differently(e.g., different heights from the ground) than a sensor that capturedthe map data. This difference may result in a reduced overlap score whendata derived from the two sensors is compared because, for example, theperspective of the vehicle's sensor is different from the perspective ofthe sensor that was used to generate the map. At a given location,different perspectives can cause certain objects or map features to beoccluded or not occluded. In some cases, the reduction in overlap score,even for the overlap score at a location within the map that correspondsto the vehicle's true location, may result in the autonomous vehiclefailing to recognize its current position from the map data. This maycause the vehicle to provide a warning, to exit from autonomous driving,or to rely on less accurate means of estimating its position.

To improve the determination of overlap between vehicle's capturedsensor data (“vehicle data”) and map data, the disclosed methods,devices, and systems may detect differences between the vehicle data andmap data that can be explained by differences in positions of therespective sensors used to collect the data. For example, in someaspects, if a point in the vehicle data does not have a match in the mapdata, a ray may be traced from the vehicle's sensor position through thenon-matching point in the vehicle data. If the traced ray intersects apoint in the map data, the non-matching point may be included in theoverlap score determination. Otherwise it may not be included. Forexample, in some aspects, an overlap score is a ratio of a number ofpoints in the vehicle data that match points in the map data, to a totalnumber of points in the vehicle data. If the non-matching point is notincluded in the overlap score, the total number of points does notinclude the non-matching point.

Some aspects may determine points within the map data that are occluded.For example, these points may not have been visible to a sensor used tocollect the map data. If a non-matching point in the vehicle data fallswithin an occluded portion of the map data, the non-matching point maynot be included in the overlap score determination. Otherwise, thenon-matching point may be included in the overlap score determination.Use of the above techniques may improve an overlap score'srepresentation of how well the vehicle data matches the map data.

FIG. 1 is an overview diagram of an autonomous driving truck. Thevehicle 102 includes a sensor 104, a controller or vehicle computingsystem 106, and a map database 118. The sensor 104 captures point clouddata representing a scene 105. In the illustrated embodiment, the sensor104 is positioned on the roof of the truck, resulting in a distance ofD₁ between the ground and the sensor 104. The sensor 104 may be a LIDARsensor. In some other aspects, the sensor 104 may be a visual sensor oran infrared sensor. The sensor 104 may be comprised of multiple physicalsensors or multiple physical sensor devices. The sensor 104 may providethree-dimensional data. For example, data in an X, Y, and Z dimensionmay be obtained from the sensor 104.

The controller or vehicle computing system 106 compares data collectedby the sensor 104 to map data included in the map database 118. Asdiscussed above, the controller or vehicle computing system 106 computesan overlap score between the data collected by the sensor 104 and themap data in the map database 118 to determine a position of the vehicle102.

FIG. 2 shows an example embodiment of a map data collection vehicle. Themap data collection vehicle 202 includes a sensor 204, a controller 206,and the map database 118. The sensor 204 operationally captures pointcloud data representing a scene 205 in front of the vehicle 202. Thepoint cloud data captured by the sensor 204 may includethree-dimensional data, such as data across each of X, Y, and Zdimension. The controller 206 stores map data derived from point clouddata collected by the sensor 204 in the map database 118. The map datamay reflect a perspective of the sensor 204, which is located at adistance D₂ from the ground. Note that distance D₂ is a differentdistance from that of distance D₁, discussed above with respect to FIG.1 and the vehicle 102.

With reference to the figures, example embodiments of the presentdisclosure will be discussed in further detail. FIG. 3A is a blockdiagram of an example system 300 to control the navigation of a vehicle102 according to example embodiments of the present disclosure. Theautonomous vehicle 102 is capable of sensing its environment andnavigating with little to no human input. The autonomous vehicle 102 canbe a ground-based autonomous vehicle (e.g., car, truck, bus, etc.), anair-based autonomous vehicle (e.g., airplane, drone, helicopter, orother aircraft), or other types of vehicles (e.g., watercraft). Theautonomous vehicle 102 can be configured to operate in one or moremodes, for example, a fully autonomous operational mode and/or asemi-autonomous operational mode. A fully autonomous (e.g.,self-driving) operational mode can be one in which the autonomousvehicle can provide driving and navigational operation with minimaland/or no interaction from a human driver present in the vehicle. Asemi-autonomous (e.g., driver-assisted) operational mode can be one inwhich the autonomous vehicle operates with some interaction from a humandriver present in the vehicle.

As discussed above, the autonomous vehicle 102 can include one or moresensors 104, a controller or vehicle computing system 106, and one ormore vehicle controls 108. The vehicle controls 108 may include one ormore of the vehicle computing system 106 can assist in controlling theautonomous vehicle 102. In particular, the vehicle computing system 106can receive sensor data from the one or more sensors 104, attempt tocomprehend the surrounding environment by performing various processingtechniques on data collected by the sensors 104, and generate anappropriate motion path through such surrounding environment. Thevehicle computing system 106 can control the one or more vehiclecontrols 108 to operate the autonomous vehicle 102 according to themotion path.

The vehicle computing system 106 can include one or more processors 130and at least one memory 132. The one or more processors 130 can be anysuitable processing device (e.g., a processor core, a microprocessor, anASIC, a FPGA, a controller, a microcontroller, etc.) and can be oneprocessor or a plurality of processors that are operatively connected.The memory 132 can include one or more non-transitory computer-readablestorage mediums, such as RAM, ROM, EEPROM, EPROM, flash memory devices,magnetic disks, etc., and combinations thereof. The memory 132 can storedata 134 and instructions 136 which are executed by the processor 130 tocause vehicle computing system 106 to perform operations. In someimplementations, the one or more processors 130 and at least one memory132 may be comprised in one or more computing devices, such as computingdevice(s) 129, within the vehicle computing system 106.

In some implementations, vehicle computing system 106 can further beconnected to, or include, a positioning system 120. Positioning system120 can determine a current geographic location of the autonomousvehicle 102. The positioning system 120 can be any device or circuitryfor analyzing the position of the autonomous vehicle 102. For example,the positioning system 120 can determine actual or relative position byusing a satellite navigation positioning system (e.g. a GPS system, aGalileo positioning system, the Global Navigation satellite system(GLONASS), the BeiDou Satellite Navigation and Positioning system), aninertial navigation system, a dead reckoning system, based on IPaddress, by using triangulation and/or proximity to cellular towers orWiFi hotspots, and/or other suitable techniques for determiningposition. The position of the autonomous vehicle 102 can be used byvarious systems of the vehicle computing system 106.

As illustrated in FIG. 3A, in some embodiments, the vehicle computingsystem 106 can include a perception system 110, a prediction system 112,and a motion planning system 114 that cooperate to perceive thesurrounding environment of the autonomous vehicle 102 and determine amotion plan to control the motion of the autonomous vehicle 102accordingly. In some implementations, the vehicle computing system 106can also include a feature extractor/concatenator 122 and a speed limitcontext awareness machine-learned model 124 that can be provide data toassist in determining the motion plan to control the motion of theautonomous vehicle 102.

In particular, in some implementations, the perception system 110 canreceive sensor data from the one or more sensors 104 that are coupled toor otherwise included within the autonomous vehicle 102. As examples,the one or more sensors 104 can include a Light Detection and Ranging(LIDAR) system, a Radio Detection and Ranging (RADAR) system, one ormore cameras (e.g., visible spectrum cameras, infrared cameras, etc.),and/or other sensors. The sensor data can include information thatdescribes the location of objects within the surrounding environment ofthe autonomous vehicle 102.

As one example, for LIDAR systems, the sensor data can include thelocation (e.g., in three-dimensional space relative to the LIDAR system)of a number of points that correspond to objects that have reflected aranging laser. For example, LIDAR system can measure distances bymeasuring the Time of Flight (TOF) that it takes a short laser pulse totravel from the sensor to an object and back, calculating the distancefrom the known speed of light.

As another example, for RADAR systems, the sensor data can include thelocation (e.g., in three-dimensional space relative to RADAR system) ofa number of points that correspond to objects that have reflected aranging radio wave. For example, radio waves (pulsed or continuous)transmitted by the RADAR system can reflect off an object and return toa receiver of the RADAR system, giving information about the object'slocation and speed. Thus, RADAR system can provide useful informationabout the current speed of an object.

As yet another example, for one or more cameras, various processingtechniques (e.g., range imaging techniques such as, for example,structure from motion, structured light, stereo triangulation, and/orother techniques) can be performed to identify the location (e.g., inthree-dimensional space relative to the one or more cameras) of a numberof points that correspond to objects that are depicted in imagerycaptured by the one or more cameras. Other sensor systems can identifythe location of points that correspond to objects as well.

Thus, the one or more sensors 104 can be used to collect sensor datathat includes information that describes the location (e.g., inthree-dimensional space relative to the autonomous vehicle 102) ofpoints that correspond to objects within the surrounding environment ofthe autonomous vehicle 102.

In addition to the sensor data, the perception system 110 can retrieveor otherwise obtain map data 118 that provides detailed informationabout the surrounding environment of the autonomous vehicle 102. The mapdata 118 can provide information regarding: the identity and location ofdifferent travel ways (e.g., roadways), road segments, buildings, orother items or objects (e.g. lampposts, crosswalks, curbing, etc.); thelocation and directions of traffic lanes (e.g., the location anddirection of a parking lane, a turning lane, a bicycle lane, or otherlanes within a particular roadway or other travel way); traffic controldata (e.g., the location and instructions of signage, traffic lights, orother traffic control devices); and/or any other map data that providesinformation that assists the vehicle computing system 106 incomprehending and perceiving its surrounding environment and itsrelationship thereto.

The perception system 110 can identify one or more objects that areproximate to the autonomous vehicle 102 based on sensor data receivedfrom the one or more sensors 104 and/or the map data 118. In particularin some implementations, the perception system 110 can determine, foreach object, state data that describes a current state of such object.As examples, the state data for each object can describe an estimate ofthe object's: current location (also referred to as position); currentspeed; current heading (also referred to together as velocity); currentacceleration; current orientation; size/footprint (e.g., as representedby a bounding shape such as a bounding polygon or polyhedron); class(e.g. vehicle versus pedestrian versus bicycle versus other), yaw rate;and/or other state information.

In some implementations, the perception system 110 may determine statedata for each object over a number of iterations. In particular, theperception system 110 can update the state data for each object at eachiteration. Thus, the perception system 110 can detect and track objects(e.g., vehicles, pedestrians, bicycles, and the like) that are proximateto the autonomous vehicle 102 over time.

The prediction system 112 may receive the state data from the perceptionsystem 110 and predict one or more future locations for each objectbased on such state data. For example, the prediction system 112 canpredict where each object will be located within the next 5 seconds, 10seconds, 20 seconds, etc. As one example, an object can be predicted toadhere to its current trajectory according to its current speed. Asanother example, other, more sophisticated prediction techniques ormodeling can be used.

The motion planning system 114 may determine a motion plan for theautonomous vehicle 102 based at least in part on the predicted one ormore future locations for the object provided by the prediction system112 and/or the state data for the object provided by the perceptionsystem 110. Stated differently, given information about the currentlocations of objects and/or predicted future locations of proximateobjects, the motion planning system 114 can determine a motion plan forthe autonomous vehicle 102 that best navigates the autonomous vehicle102 relative to the objects at such locations.

As one example, in some implementations, the motion planning system 114can determine a cost function for each of one or more candidate motionplans for the autonomous vehicle 102 based at least in part on thecurrent locations and/or predicted future locations of the objects. Forexample, the cost function can describe a cost (e.g., over time) ofadhering to a particular candidate motion plan. For example, the costdescribed by a cost function can increase when the autonomous vehicle102 approaches a possible impact with another object and/or deviatesfrom a preferred pathway (e.g., a preapproved pathway).

Thus, given information about the current locations and/or predictedfuture locations of objects, the motion planning system 114 candetermine a cost of adhering to a particular candidate pathway. Themotion planning system 114 can select or determine a motion plan for theautonomous vehicle 102 based at least in part on the cost function(s).For example, the candidate motion plan that minimizes the cost functioncan be selected or otherwise determined. The motion planning system 114can provide the selected motion plan to a vehicle controller 116 thatcontrols one or more vehicle controls 108 (e.g., actuators or otherdevices that control gas flow, acceleration, steering, braking, etc.) toexecute the selected motion plan.

FIG. 3B is an example of an expanded view of the autonomous vehicle 102.As discussed above, the autonomous vehicle 102 may include the sensor104, the vehicle controller or vehicle computing system 106, a motorcontroller 210, a steering controller 212, a braking controller 214, andthe map database 118. The controller 106 is operably connected to eachof the sensor 104, motor controller 210, steering controller 212 andbraking controller 214, via any known interconnect technology. In FIG.3, this is illustrated as a bus 230. The vehicle controller 106 may beconfigured to capture multiple point cloud data sets from the sensor 104and compare the point cloud data sets to map data in the map database118. Based on the comparison, the controller 106 may determine aposition of the vehicle 102. The vehicle controller 106 may control theposition and/or speed of the vehicle 102 by issuing commands to one ormore of the motor controller 210, steering controller 212, and/orbraking controller 214. For example, if the controller 106 determines aspeed of the truck should be increased, the controller 106 may transmita command to the motor controller 210 indicating an increased level offuel is to be provided to the motor. In embodiments utilizing electricmotors, the vehicle controller 106 may transmit a command to the motorcontroller 210 indicating an increased current or voltage is to beprovided to the motor. If the vehicle controller 106 determines aposition of the vehicle 102 should be adjusted to the left or right, thecontroller 106 may send a command indicating same to the steeringcontroller 212.

FIG. 4 is an expanded view of an example controller or vehicle computingsystem 106. The example controller or vehicle computing system 106 ofFIG. 4 includes one or more hardware processors 130, a hardware memoryor memories 132, and one or more interfaces 440. The hardwareprocessor(s) 130, memories 132, and interfaces 440 may be operablyconnected via any known interconnect technology, such as a bus 430. Insome aspects, instructions stored in the memory/memories 132 mayconfigure the one or more hardware processors 130 to perform one or moreof the functions discussed below to provide for autonomous control of avehicle, such as the vehicle 102. The interface(s) 440 may provide forelectronic communication between the controller 106 and one or more ofthe motor controller 210, steering controller 212, braking controller214, sensor 104, and/or map database 118.

FIG. 5 shows example scenes captured by LIDAR sensors) of an autonomousvehicle and a map generating vehicle. While a LIDAR sensor may capturepoint cloud data, for ease of illustration the scenes 502, 510, and 520are shown as two dimensional images. An autonomous vehicle sensor maycapture point cloud data for the scene 502. The scene 502 may becaptured, in some aspects, by the sensor 104. The scene 502 shows arelatively straight road 504, a tree 506, and a pedestrian 508. Thescene 502, shows that the tree 506 is a distance D₃ from the LIDARsensor (e.g. 104) capturing the scene 502.

Point cloud data for a scene 510 may be captured by a vehicle generatingmap data. For example, point cloud data for the scene 510 may becaptured by the sensor 204 of the vehicle 202. The scene 510 also showsthe road 504 and the tree 506. The tree 506 in the scene 510 is adistance D₄ from the imaging sensor 204. D4 is less than D₃ in the scene502. Thus, the scene 510 may be captured when the vehicle 202 ispositioned closer to the tree than the vehicle 102 was positioned whencapturing the scene 502.

Point cloud data for the scene 520 may also be captured by a vehiclegenerating map data. The scene 520 shows the road 504 and the tree 506.The tree 506 in the scene 520 is further from the LIDAR sensor capturingthe scene 520 (e.g. a distance D_(4′), not shown) than in either thescene 510 or 502.

Some aspects may generate a first overlap score 552 for point cloud datarepresenting the scenes 502 and 510, and a second overlap score 554 forpoint cloud data representing scenes 502 and 520. The two overlap scores552 and 554 may be compared, with results of the comparison used toselect a set of point cloud data for a scene that is closest to thescene 502 captured by the autonomous vehicle.

To generate an overlap score, a positional relationship between twoscenes may be determined. For example, in some aspects, a “best fit”process may be performed so as to establish a correspondence betweenpoint cloud data representing the scene 502 and point cloud datarepresenting the scene 510, and similarly to establish a correspondencebetween point cloud data representing the scene 502 and point cloud datarepresenting the scene 520.

FIG. 6 is a visual representation of a best fit correspondence betweenpoint cloud data 502 i and 510 i representing the scenes 502 and 510respectively. As shown in FIG. 6, aligning features in each of the pointcloud data sets 502 i and 510 i may result in offsets in one or moredimensions between the point cloud data sets 502 i and 510 i. Forexample, point cloud data 502 i is shown, in a simplified twodimensional view, offset to the right and below the point cloud data 510i to obtain the best fit. A size of the offsets in a first and seconddimension is shown by D₅ and D₆ respectively. In some aspects, after thecorrespondence between point cloud data 502 i and point cloud data 510 iis established as visually indicated in FIG. 6 (in two dimensions onlyfor ease of illustration), an overlap score may then be determined basedon portions of each set of point cloud data representing a sharedthree-dimensional space. The shared three-dimensional space isestablished based on the correspondence. In some aspects, correspondencebetween two sets of point cloud data establishes coordinate offsetsbetween points in each of the point clouds that represent a common pointin three-dimensional space. For example, if the point cloud data 502 iis offset to the right relative to point cloud data 510 i by ten (10)pixels, the correspondence in the horizontal dimension will indicatethat data at a position (x, y, z) in point cloud data 502 i is to becompared to data at position (x+10,y,z) in point cloud data 510 i.

In some aspects, after the correspondence illustrated in FIG. 6 isestablished, the portion of three-dimensional space that is shared bythe two sets of point cloud data is illustrated as region 610. Anoverlap score for region 610 of the two point clouds may then bedetermined in some aspects.

FIG. 7 shows the two sets of point cloud data 502 i and 510 i. Pointcloud data 502 i represents the scene 502 of FIG. 5 in three dimensions(only two dimensions shown in FIG. 7), while point cloud data 510 irepresents scene 510 of FIG. 5 in three dimensions (only two dimensionsshown in FIG. 7). Regions 610 a and 610 b are shown within each of pointcloud data 502 i and 510 i. These regions 610 a-b represent the region610 shown in FIG. 6, but contained within each of the respective pointcloud data 502 i and 510 i.

Magnified views of portions of regions 610 a and 610 h are shown as 710a and 710 b respectively. Portion 710 a includes four points 720 a-dwhile portion 710 b includes three points 722 a-c. The portions 710 a-bare shown in two dimensions for ease of illustration, but the portionsshown are intended to represent point cloud data in a three-dimensionalspace. A location within portion 710 b corresponding to point 720 d inregion 610 a is shown as 722 d. The two points 720 d and 722 d may beconsidered corresponding or “matching” because they have equivalentcoordinates in their respective images or point clouds after the imagesor point clouds are aligned, for example, via a registration process. Insome aspects, if the two points have coordinates within a predeterminedrange of each other, they may also be considered corresponding. Thepredetermined range may be provided to allow for some error in alignmentof point clouds. For example, in some of the disclosed embodiments, thepredetermined range may represent a relatively small distance error inthe alignment, such as less than any of 20, 19, 18, 17, 16, 15, 14, 13,12, 11, 10, 9, 8, 7, 6, 5, 4, 2, or 1 centimeters. In some embodiments,an overlap score may relate a number of matching points to a totalnumber of points. Thus, in the simplified example of FIG. 7, someembodiments would determine an overlap score of 0.75 for the twoportions 710 a and 710 b. This approach may be extended to encompass theentirety of regions 610 a-b and/or point cloud data 502 i and 510 i.

FIG. 8 shows example two dimensional representations of point cloud dataused to determine an overlap score. The point cloud data 802 may becaptured from an autonomous vehicle and compared to map data includingthe point cloud data 810. The point cloud data 802 shows a road 820,bridge 822, and building 824. The map point cloud data 810 also includesthe road 820, bridge 822, and building 824. The map point cloud data 810differs from the vehicle point cloud data 802 in that a portion of thebuilding 826 is visible above the bridge 822 in the vehicle point clouddata 802 but not in the map point cloud data 810. In some aspects, thisdifference may be caused by a difference in height of the two LIDARsensors that captured the two sets of point cloud data 802 and 810. Forexample, as shown in FIGS. 1 and 2, the sensor 104, mounted on a roof ofthe vehicle 102, and used to capture point cloud data 802, may befurther from the ground (i.e. distance D₁) than the sensor 204, mountedon a roof of the car 202 (i.e. distance D2) and used to capture mappoint cloud data 810. An overlap score based on the point cloud data 802and 810 may be reduced due to the difference in perspective caused bythe different distances D1 and D2, and the resulting building portion826 appearing in point cloud 802 but not in point cloud data 810.

Aspects disclosed may determine whether a portion of a three-dimensionalspace including the building portion 826 in point cloud data 802 wasobscured in point cloud data 810. In some aspects, this determinationmay be performed in response to determining that the portion 826 inpoint cloud data 802 is not present in point cloud data 810. In someaspects, if any portion of three-dimensional space including thebuilding portion 826 was obscured in point cloud data 810, that portionmay not be included in an overlap score based on the point cloud data802 and point cloud data 810. For example, if an obscured portion of thespace occupied by building portion 826 included a particular number ofdata points, those particular number of data points would not beincluded in the overlap score, in that a total number of points wouldnot include the particular number of points.

FIG. 9 illustrates tracing of a ray from a laser source to adestination. FIG. 9 shows the scene 502. Point cloud data representingthe scene 502 may be captured by an autonomous vehicle, such as theautonomous vehicle 102 discussed above with respect to at least FIGS. 1and 3. FIG. 9 also shows one embodiment of map data 910. The map data910 may include point cloud data captured by a map data collectionvehicle, such as the map data collection vehicle 202 discussed abovewith respect to FIG. 2. The map data 910 may not include the tree 506 orthe pedestrian 508.

As discussed above, point cloud data representing the scene 502 may becompared to point cloud data representing the scene 910 when determininga position of an autonomous vehicle in at least some of the disclosedembodiments. The comparison of the two point cloud data sets mayidentify points representing the tree 506 in scene 502 that do not havecorresponding points in the point cloud representing the scene 510,since the tree 506 is not present in the scene 506. These points may beconsidered non-matching points. In other words, corresponding or“matching” points may be two points in two respective point cloud datasets that have equivalent coordinates after the two point cloud datasets are aligned, for example, via a registration process. In someaspects, some degree of error may be provided for in determining whethertwo points are corresponding. For example, in some aspects, two pointsmay be considered corresponding if they are within a first predeterminednumber of units in a first axis (such as an X axis), a secondpredetermined number of units in a second axis (such as a Y axis), and athird predetermined number of units in a third axis (such as a Z axis).

In some aspects, to determine whether each point representing the treein scene 502 should be included in an overlap score between the twoscenes 502 and 910, ray tracing data may be generated for the pointcloud data representing the scene 910. The ray tracing data may be usedto determine if a point exists in the scene 910's point cloud data atany position along the path of the ray (e.g. ray 920 in FIG. 9). Asource of the ray may be a laser source position of a LIDAR sensorcapturing the scene 910. The ray may intersect a location in the scene910 occupied by a non-matching point in the point cloud data for scene502. The ray may also extend beyond the non-matching point. If the rayintersects a point in the point cloud data representing the scene 910,then the non-matching point in the scene 502 may be included in anoverlap score. If the ray does not intersect any point in the pointcloud data representing the scene 910, in some embodiments, thenon-matching point may not be included in the overlap score.

FIG. 10 is an example of a comparison of point cloud data captured by anautonomous vehicle (e.g. 102) and data included in a map. FIG. 10illustrates that with some points, both a normal vector associated witha point and the point itself match. For some additional portion ofpoints, locations of the points match between the two data but thenormal vectors are different. This may occur, for example, with foliage,which may be repositioned frequently by wind or even in some aspects bypassing vehicles. For some other points, there may not be a point in themap data at a location of a point in the vehicle's point cloud.

FIG. 11 is a flowchart of an example method of controlling an autonomousvehicle. The process 1100 discussed below with respect to FIG. 11 may beperformed, in some aspects, by the vehicle controller 106. For example,instructions stored in the memory 132 may configure the one or morehardware processors 130 to perform one or more of the functionsdiscussed below with respect to FIG. 11 and process 1100.

Process 1100 determines an overlap score. The overlap score indicates anamount of overlap between position data collected by a first vehicle,for example, from a LIDAR sensor, and map data. The map data may begenerated prior to performance of the process 1100. The map data may bebased on data obtained from a separate sensor mounted on a differentsecond vehicle. As discussed above, differences in height between thefirst sensor and the second sensor may result in reduced overlap betweenthe vehicle data and the map data. In some aspects, this may havedeleterious effects if not properly compensated.

In block 1110, a point cloud is captured with a LIDAR sensor. Forexample, in some aspects, point cloud data representing the scene 105may be captured by the sensor 104. The point cloud data isrepresentative of a surrounding of an autonomous vehicle. For example,as discussed above with respect to FIG. 1, the sensor 104 may capturethe scene 105 immediately in front of the vehicle 102.

In block 1120, a point is identified in the point cloud data as anon-matching point in response to the point having no correspondingpoint in a map. The map may also include three-dimensional data or pointcloud data. The three-dimensional space represented by each of the pointcloud data and the map is compared. In some aspects, at least a portionof points in the captured point cloud data will match a point in the mapdata. Another portion of points may not have a corresponding matchingpoint in the map. For example, if a point in the point cloud datarepresents a reflection of LIDAR signals from an object at a location inthe point cloud, the corresponding location in the map may be empty, orin other words, may not indicate a reflection of LIDAR data.

Corresponding or “matching” points may be two points in the capturedpoint cloud data and the map data respectively that have equivalentcoordinates after the two point cloud data sets are aligned, forexample, via a registration process. In some aspects, some degree oferror may be provided for in determining whether the two points arecorresponding or matching. For example, in some aspects, two points maybe considered corresponding if they are within a first predeterminednumber of units in a first axis (such as an X axis), a secondpredetermined number of units in a second axis (such as a Y axis), and athird predetermined number of units in a third axis (such as a Z axis).In some aspects, if the two points have coordinates within apredetermined range of each other, they may also be consideredcorresponding. The predetermined range may be provided to allow for someerror in alignment of point clouds. For example, in some of thedisclosed embodiments, the predetermined range may represent arelatively small absolute distance error in the alignment, such as lessthan any of 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5,4, 2, or 1 centimeters.

In some aspects, a height parameter for the map may be determined. Forexample, some aspects may store information relating to distance D₂ withthe map generated by the vehicle 202. The height parameter may becompared to a height of the one or more Lidar sensors used to capturethe point cloud in block 1110 (e.g. D₁). The point-cloud data may beadjusted based on the comparison.

In some aspects, an angle of the one or more LIDAR sensors with respectto a reference plane may be determined, and compared with an angleassociated with the map data. The point-cloud data based on the angle insome aspects. After one or more of the adjustments, the determination ofwhether the point is a matching point or a non-matching point may bemade.

In block 1130, a determination is made as to whether the non-matchingpoint is used in an overlap score. The determination is based on one ormore comparisons of the point cloud data and the map. For example, insome aspects, in some aspects, block 1130 may determine whether thecorresponding position in the map is obscured in the map data. Asdiscussed above, in some aspects, because of differences in perspectivebetween a LIDAR sensor used to capture the map data, and a LIDAR sensorused to capture point cloud data for an autonomous vehicle, some objectsvisible to the LIDAR sensor(s) of the autonomous vehicle may not bevisible to the LIDAR sensor collecting data for the map.

Some aspects may generate ray-tracing data representing a tracing of aray from a laser source of the one or more Lidar sensors to a locationin the map corresponding to the location of the non-matching point. If apoint is at the location in the map, the non-matching point may beincluded in the determination of the overlap sore. If there is no pointat the location in the map, the non-matching point may not be includedin the determination of the overlap score.

Some aspects may determine whether the non-matching point corresponds toa non-occluded point of the map; and include the non-matching point inthe determination of the overlap score in response to the non-matchingpoint corresponding to a non-occluded point. For example, as discussedin FIG. 8, some objects, such as the building 826, may be represented bythe point cloud data representing a scene captured by an autonomousvehicle, but may be obscured in point cloud data of the map. In thesecases, non-matching points may not be considered in an overlap score.

In block 1140, the overlap score is determined based on the includedpoints and the map. The overlap score relates a number of point that mapto the map to a total number of points included in the determination ofthe overlap score.

In block 1150, a position of the vehicle is determined based on theoverlap score. For example, as discussed above, an overlap score may bedetermined for a plurality of map point cloud data sets. A set of pointcloud data in the map having the highest overlap score with vehiclepoint cloud data may be selected as most closely approximating thevehicle position. Offsets from the selected map point cloud data maythen be determined to determine a more precise position of the vehiclerelative to the selected map point cloud data.

In block 1160, the vehicle is controlled based on the determinedposition. For example, as discussed above, the controller 106 may send acommand to one or more of the motor controller 210, steering controller212, and braking controller 214 to control the vehicle based on thedetermined position. For example, if the determined position indicatesthe vehicle is not centered in a lane of travel, the controller 214 maysend a command to the steering controller 212 to adjust the path of thevehicle to move the vehicle closer to the center of the lane. As anotherexample, if the determined position is within a predetermined thresholddistance of a curve in a road, the controller 106 may send a command tothe braking controller 214 and/or motor controller 210 to reduce a speedof the vehicle.

In some aspects, process 1100 includes determining a motion plan for theautonomous vehicle. The motion plan may be based in some aspects on theoverlap score. Process 1100 may include sending a signal to one or moreof a steering controller, engine controller, or braking controller basedon the motion plan.

As used herein, the term “machine-readable medium,” “computer-readablemedium,” or the like may refer to any component, device, or othertangible medium able to store instructions and data temporarily orpermanently. Examples of such media may include, but are not limited to,random-access memory (RAM), read-only memory (ROM), buffer memory, flashmemory, optical media, magnetic media, cache memory, other types ofstorage (e.g., Electrically Erasable Programmable Read-Only Memory(EEPROM)), and/or any suitable combination thereof. The term“machine-readable medium” should be taken to include a single medium ormultiple media (e.g., a centralized or distributed database, orassociated caches and servers) able to store instructions. The term“machine-readable medium” may also be taken to include any medium, orcombination of multiple media, that is capable of storing instructions(e.g., code) for execution by a machine, such that the instructions,when executed by one or more processors of the machine, cause themachine to perform any one or more of the methodologies describedherein. Accordingly, a “machine-readable medium” may refer to a singlestorage apparatus or device, as well as “cloud-based” storage systems orstorage networks that include multiple storage apparatus or devices. Theterm “machine-readable medium” excludes transitory signals per se.

Where a phrase similar to “at least one of A, B, or C,” “at least one ofA, B, and C,” “one or more of A, B, or C,” or “one or more of A, B, andC” is used, it is intended that the phrase be interpreted to mean that Aalone may be present in an embodiment, B alone may be present in anembodiment, C alone may be present in an embodiment, or any combinationof the elements A, B, and C may be present in a single embodiment; forexample, A and B, A and C, B and C, or A and B and C may be present.

Changes and modifications may be made to the disclosed embodimentswithout departing from the scope of the present disclosure. These andother changes or modifications are intended to be included within thescope of the present disclosure, as expressed in the following claims.

A portion of the disclosure of this patent document contains materialthat is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in the Patent and TrademarkOffice patent files or records, but otherwise reserves all copyrightrights whatsoever. The following notice applies to the software and dataas described below and in the drawings that form a part of thisdocument: Copyright 2017, Uber, Inc., All Rights Reserved.

I claim:
 1. A method of controlling a vehicle, comprising: capturing,via hardware processing circuitry, point-cloud data representative of asurrounding environment of an autonomous vehicle with one or more LI DARsensors, each point in the point-cloud data representing a reflectionfrom the surrounding environment; identifying, via the hardwareprocessing circuitry, a first point in the point cloud data as anon-matching point based at least on the first point having nocorresponding point in a map; selectively including, via the hardwareprocessing circuitry, the non-matching first point in a set of pointsbased on one or more comparisons of the point cloud data and the map;determining, via the hardware processing circuitry, a first overlapscore by relating a number of points in the set of points that havecorresponding matching points on the map to a total number of points inthe set of points, wherein determining the first overlap score comprisesdetermining, based on a plurality of candidate positions of theautonomous vehicle within the map, a plurality of overlap scoresincluding the first overlap score; and determining a position of theautonomous vehicle on the map based on the first overlap score and themap, wherein determining the position of the autonomous vehiclecomprises comparing the plurality of overlap scores to determine theposition of the autonomous vehicle; and controlling, via the hardwareprocessing circuitry, the autonomous vehicle based on the position. 2.The method of claim 1, wherein the selectively including thenon-matching first point in the set of points comprises: generatingray-tracing data representing a tracing of a ray from a laser source ofthe one or more LIDAR sensors through the non-matching first point;determining that the ray intersects a reference point in the map; and inresponse to determining that the ray intersects the reference point inthe map, including the non-matching first point in the set of points. 3.The method of claim 1, wherein the selectively including thenon-matching first point in the set of points comprises: determiningthat the non-matching first point corresponds to a non-occluded point ofthe map; and including the non-matching first point in the set of pointsin response to the non-matching first point corresponding to anon-occluded point.
 4. The method of claim 1, further comprising:determining a height of the one or more LIDAR sensors; and adjusting thepoint-cloud data based on the height, wherein the selective inclusion ofthe non-matching first point in the set of points is based on theadjusted point cloud data.
 5. The method of claim 4, further comprising:determining a height parameter of the map; comparing the heightparameter to the height of the one or more LIDAR sensors; and adjustingthe point-cloud data based on the comparison.
 6. The method of claim 4,further comprising: determining an angle of the one or more LIDARsensors with respect to a reference plane; and adjusting the point-clouddata based on the angle.
 7. The method of claim 1, wherein controllingthe autonomous vehicle based on the position comprises: determining amotion plan for the autonomous vehicle; and sending a signal to one ormore of a steering controller, engine controller, or braking controllerbased on the motion plan.
 8. A vehicle, comprising: one or more lightdetection and ranging (LIDAR) sensors; one or more hardware processors;one or more tangible, non-transitory, computer readable media thatcollectively store instructions that when executed by the one or morehardware processors cause the one or more hardware processors to performoperations, the operations comprising: capturing point-cloud datarepresentative of a surrounding of the vehicle, each point in thepoint-cloud data representing a reflection from the surroundingenvironment; identifying a first point in the point cloud data as anon-matching point based at least on the first point having nocorresponding point in a map; selectively including the non-matchingfirst point in a set of points based on one or more comparisons of thepoint cloud data and the map; determining a first overlap score byrelating a number of points in the set of points that have correspondingmatching points on the map to a total number of points in the set ofpoints, wherein determining the first overlap score comprisesdetermining, based on a plurality of candidate positions of theautonomous vehicle within the map, a plurality of overlap scoresincluding the first overlap score; determining a position of theautonomous vehicle on the map based on the first overlap score and themap, wherein determining the position of the autonomous vehiclecomprises comparing the plurality of overlap scores to determine theposition of the autonomous vehicle; and controlling the autonomousvehicle based on the position.
 9. The vehicle of claim 8, whereinselectively including the non-matching first point in the set of pointscomprises: generating ray-tracing data representing a tracing of a rayfrom a laser source of the one or more LIDAR sensors to a destinationpoint that intersects the non-matching point; determining that the rayintersects a reference point in the map; and in response to determiningthat the ray intersects the reference point in the map, including thenon-matching point in the set of points.
 10. The vehicle of claim 8,wherein selectively including the non-matching first point in the set ofpoints comprises: determining that the non-matching point corresponds toa non-occluded point of the map; and including the non-matching point inthe set of points in response to the non-matching point corresponding toa non-occluded point.
 11. The vehicle of claim 8, the operations furthercomprising: determining a height of the one or more LIDAR sensors; andadjusting the point-cloud data based on the height, wherein theselective inclusion of the non-matching point in the set of points isbased on the adjusted point cloud data.
 12. The vehicle of claim 11, theoperations further comprising: determining a height parameter of themap; comparing the height parameter to the height of the one or moreLIDAR sensors; and adjusting the point-cloud data based on thecomparison.
 13. The vehicle of claim 11, the operations furthercomprising: determining an angle of the one or more LIDAR sensors withrespect to a reference plane; and adjusting the point-cloud data basedon the angle.
 14. The vehicle of claim 8, wherein controlling theautonomous vehicle based on the position comprises: determining a motionplan for the autonomous vehicle; and sending a signal to one or more ofa steering controller, engine controller, or braking controller based onthe motion plan.
 15. A computing system for a vehicle, comprising: oneor more hardware processors; one or more tangible, non-transitory,computer readable media that collectively store instructions that whenexecuted by the one or more hardware processors cause the one or morehardware processors to perform operations, the operations comprising:capturing point-cloud data representative of a surrounding of thevehicle with one or more LIDAR sensors, each point in the point-clouddata representing a reflection from the surrounding environment;identifying a first point in the point cloud data as a non-matchingpoint based at least on the first point having no corresponding point ina map; selectively including the non-matching first point in a set ofpoints based on one or more comparisons of the point cloud data and themap; determining a first overlap score by relating a number of points inthe set of points that have corresponding matching points on the map toa total number of points in the set of points, wherein determining thefirst overlap score comprises determining, based on a plurality ofcandidate positions of the autonomous vehicle within the map, aplurality of overlap scores including the first overlap score;determining a position of the autonomous vehicle on the map based on thefirst overlap score and the map, wherein determining the position of theautonomous vehicle comprises comparing the plurality of overlap scoresto determine the position of the autonomous vehicle; and controlling theautonomous vehicle based on the position.
 16. The computing system ofclaim 15, wherein the selective including of the non-matching firstpoint in the set of points comprises: generating ray-tracing datarepresenting a tracing of a ray from a laser source of the one or moreLIDAR sensors to a destination point that intersects the non-matchingpoint; determining that the ray intersects a reference point in the map;and in response to determining that the ray intersects the referencepoint in the map, including the non-matching point in the set of points.17. The computing system of claim 15, wherein selectively including thenon-matching first point in the set of points comprises: determiningthat the non-matching point corresponds to a non-occluded point of themap; and including the non-matching point in the set of points inresponse to the non-matching point corresponding to a non-occludedpoint.
 18. The method of claim 1, wherein the selective includingincludes the first non-matching point in the set of points, the methodfurther comprising: determining a second non-matching point in the pointcloud data that has no corresponding point in the map; tracing a rayfrom a laser source of the one or more LIDAR sensors through the secondnon-matching point in response to the determination; determining thatthe ray does not intersect a reference point in the map; and in responseto determining that the ray does not intersect the reference point inthe map, inhibiting inclusion of the second non-matching point in theset of points.
 19. The method of claim 18, further comprisingdetermining a total number of points in the set of points that countsthe first non-matching point and does not count the second non-matchingpoint, determining a total number of matching points in the set ofpoints that does not count the first non-matching point and does notcount the second non-matching point, wherein the determining of thefirst overlap score divides the total number of matching points in theset of points by the total number of points in the set of points.